Hi Simon,

why would you imagine I would have a theory?

Well it does seem that all cats that do not have measurement restrictions on distance back that centreboards are placed built in recent years, have vertical centreboards and that incudes the Flyer ones I have bought. As far as I can see the only reason for raking centreboards back is when you want to move your Centre of Lateral Resistance further back and rules do not allow it.

I am hoping that the smaller centreboards vertical will not move CLR forward much if any at all, as the rudder blades will actualy account for a larger pecentage of the CLR, than previously, helping to balance the fact that the tip of the centreboards will be further forward.

Now for the theory .
When sailing long sailboards with swinging centreboards as the wind increased we found a effect we called railing up. This was caused by depressing the lee rail of the board on purpose which as the speed increased resulted in the centreboard lifting the board out of the water and helping it to plane, it also allowed you to point higher as you balanced the forces of the increased lift from the centreboard. No surprise I hear you say, you where using the centreboard as a lifting foil. When the wind increased it would flip the board over, to stop this we would rake the centreboard back.

My theory, raking centreboards back reduces lift . On sailboards we use to even rake them forward in light winds, which increased lift even more, but made them very hard to control .

So there you have it, I hope to get more lift which should improve windward performance . But expect it will make the boat twitchier? something I am willing to live with, I hope